Art of electroplating



Patented Feb. 20, 1934 PAT/ENT'OFFICE ART OF ELECTROPLATING George L. Wallace, Leyden, Mass., asslgnor to The Fiberloid Corporation, Indian Orchard, Mass., a corporation of Massachusetts No Drawing. Application Septembe 18, 1930,

Serial No. 482,907. 1933 3 Claims.

This invention relates to improvements in the art of electro-plating and the objects of the invention are the provision of a process for electrodepositing metal alloy and the product thereof. The numerous novel features and advantages of the invention will be observed from the follow-- ing description of the preferred form thereof.

As is well known chromium and nickel coatings have distinguishing characteristics'and for some purposes one is preferred over the other. Also it is well recognized that it is extremely diflicult if not impossible to provide a chromium coating by electro-depositing this metal directly on a cathode especially on a steel cathode.

According to this invention I provide a process wherein nickel and chromium are simultaneously deposited by electro-plating so that for instance a sheet or plate may be plated by the materials which blend to produce a surface or finish which has the favorable characteristics of a coating of either chromium or nickel and the additional advantage that it is superior to a plating of either for most purposes.

According to one mode of procedure the process of the invention is as follows: Separate anodes of chromium and of nickel are immersed in a bath which contains nickel and chromium. The chromium and nickel are deposited simultaneously on a cathode which may be a steel plate by applying an electrical current in the usual way.

Preferably the chromium anode in this case will be somewhat smaller than the nickel anode while the voltageemployed will be approximately 6 volts at about 25 amperes per square foot of area of the cathode. I have found that the nickel and chromium are deposited simultaneously and in desired proportions so as to provide a very satisfactory plating of nickel and chromium alloy.

In another way desirable results are obtained by the following: An anode of chromium and nickel alloy is employed in a solution containing chromium and nickel with a voltage and amperage as above stated. 25% chromium and 75% nickel provide a suitable anode. While from 32 ounces to 96 ounces of nickel sulphate, 16 to 32 ounces chromic carbonate and 2 ounces of boric acid per gallon of water form a very suitable solution or bath for functioning in the electrodepositing operation.

Chromic' sulphate and sodium carbonate in proper proportions in conjunction with the nickel sulphate and boric acid in water provide a suitable Renewed December 27,

solution, it being one feature of the invention to employ a solution having chromium and nickel .as a constituent thereof.

By employing the current specified in connection with the .bath and anodes described the deposit of chromium and nickel alloy is rapid andof uniform thickness and luster. Uniformity of deposit is particularly desired where large areas are to be plated, but by proceeding as outlined it has been found possible to provide large fiat plates for instance having coatings of alloy which are uniform in thickness and which do not tend to peel or crack.

The alloy deposit is more brilliant than that of a deposit of either nickel or chromium alone, it has the combined characteristics of both, is not likely to rust and has a very desirable white appearance.

I claim:

1. The process of electr c-depositing an alloy of nickel and chromium on a metal object which, consists in, immersing a cathode and an anode of chromium and nickel alloy in a bath containing sulphate of nickel, chromium carbonate and boric acid, the sulphate of nickel being from 32 80. to 96 ounces and the chromic carbonate being from 16 to 32 ounces per gallon of water.

2. The process of electro-depositing an alloy of,

nickel and chromium on a metal object which consistsin, immersing a cathode and an anode $5 of chromium and nickel alloy in a bath containing sulphate of nickel, chromic carbonate and boric acid, the sulphate of nickel being from 32 to 96 ounces per gallon of water, the chromic carbonate being from 16 to 32 ounces per gallon of water, and the boric acid being at least in the proportion of one ounce to a gallon of bath.

3. The process of electro-depositing an alloy of nickel and chromium on a metal object which consists in, immersing in a bath which contains nickel sulphate and chromic carbonate separate anodes of chromium and nickel, the chromium anode being larger than the nickel anode and a cathode and applying an electrical current having a voltage of approximately 6 volts at about 25 amperes per square foot of area of the said cathode, the said nickel sulphate being from 32 to 96 ounces and the chromic carbonate being from 16 to 32 ounces per gallon of water and the boric acid being at least in the proportion of one ounce 105 to a gallon of water.

GEORGE L. WALLACE" 

